Index: src/aphront/AphrontRequest.php
===================================================================
--- src/aphront/AphrontRequest.php
+++ src/aphront/AphrontRequest.php
@@ -466,14 +466,44 @@
   }
 
 
-  public static function getHTTPHeader($name, $default = null) {
+  /**
+   * Read the value of an HTTP header from `$_SERVER`, or a similar datasource.
+   *
+   * This function accepts a canonical header name, like `"Accept-Encoding"`,
+   * and looks up the appropriate value in `$_SERVER` (in this case,
+   * `"HTTP_ACCEPT_ENCODING"`).
+   *
+   * @param   string        Canonical header name, like `"Accept-Encoding"`.
+   * @param   wild          Default value to return if header is not present.
+   * @param   array?        Read this instead of `$_SERVER`.
+   * @return  string|wild   Header value if present, or `$default` if not.
+   */
+  public static function getHTTPHeader($name, $default = null, $data = null) {
     // PHP mangles HTTP headers by uppercasing them and replacing hyphens with
     // underscores, then prepending 'HTTP_'.
     $php_index = strtoupper($name);
     $php_index = str_replace('-', '_', $php_index);
-    $php_index = 'HTTP_'.$php_index;
 
-    return idx($_SERVER, $php_index, $default);
+    $try_names = array();
+
+    $try_names[] = 'HTTP_'.$php_index;
+    if ($php_index == 'CONTENT_TYPE' || $php_index == 'CONTENT_LENGTH') {
+      // These headers may be available under alternate names. See
+      // http://www.php.net/manual/en/reserved.variables.server.php#110763
+      $try_names[] = $php_index;
+    }
+
+    if ($data === null) {
+      $data = $_SERVER;
+    }
+
+    foreach ($try_names as $try_name) {
+      if (array_key_exists($try_name, $data)) {
+        return $data[$try_name];
+      }
+    }
+
+    return $default;
   }
 
 }
Index: src/aphront/__tests__/AphrontRequestTestCase.php
===================================================================
--- src/aphront/__tests__/AphrontRequestTestCase.php
+++ src/aphront/__tests__/AphrontRequestTestCase.php
@@ -131,4 +131,21 @@
     }
   }
 
+  public function testGetHTTPHeader() {
+    $server_data = array(
+      'HTTP_ACCEPT_ENCODING' => 'duck/quack',
+      'CONTENT_TYPE' => 'cow/moo',
+    );
+
+    $this->assertEqual(
+      'duck/quack',
+      AphrontRequest::getHTTPHeader('AcCePt-EncOdING', null, $server_data));
+    $this->assertEqual(
+      'cow/moo',
+      AphrontRequest::getHTTPHeader('cONTent-TyPE', null, $server_data));
+    $this->assertEqual(
+      null,
+      AphrontRequest::getHTTPHeader('Pie-Flavor', null, $server_data));
+  }
+
 }